1. Field of the Invention
The subject invention generally relates to a patch antenna. Specifically, the subject invention relates to an antenna having multiple patch elements that operates in multiple frequency bands.
2. Description of the Related Art
Patch antennas for receiving radio frequency (RF) signals are well known in the art. Such antennas are often utilized to receive circularly polarized RF signals. Circularly polarized RF signals are typically used in satellite-based radio communication, such as with global positioning system (GPS) and satellite digital audio radio service (SDARS) providers.
Circularly polarized RF signals are generally classified as having either right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP) based on the direction of rotation of the electric field vector of the RF signal. For example, GPS signals typically utilize RHCP and SDARS signals typically utilize LHCP. It is desirous to be able to simultaneously transmit and/or receive both RHCP and LHCP signals with a single antenna, especially in vehicle applications. Furthermore, it is desirous to integrate antennas with the glass of a vehicle, as this integration improves the aerodynamic performance of the vehicle and helps provide the vehicle with an aesthetically-pleasing, streamlined appearance.
Therefore, there is an opportunity to introduce an antenna that simultaneously radiates RHCP and LHCP RF signals on a plurality of frequency bands. Furthermore, there is an opportunity to introduce such an antenna in or on the glass of a vehicle.